The deleterious effects of excessive exposure to high sound levels have been long known. Hearing loss or impairment caused by such exposure may be irreversible in some cases. Fortunately, damage to hearing can be prevented, to a great extent, by reducing exposure to harmful sound levels and limiting the time period over which a potentially harmful exposure occurs.
In the past, exposure to excessive sound levels in the workplace has been considered a significant cause of hearing impairment. Consequently, various regulatory measures have been enacted to protect workers from dangerous levels of sound. More recently, however, the harmful effects of exposure to high sound levels outside the workplace have become apparent.
Mobile audio devices are a ubiquitous fixture of modern society. Cellular telephones, personal music players, portable gaming systems, etc. can generate audio signals at potentially damaging levels. Mobile audio device are often employed for hours each day. Users often employ such devices at sound levels that can lead to hearing impairment. For example, users of personal music players may unknowingly set device volume to produce detrimental sound levels. In some cases, the presence of background noise levels, e.g., while driving, may cause a user to increase the output volume of the device to a dangerously high level.
Regulations limiting the output sound level of mobile devices are becoming increasingly common. Some regulations may, for example, require a portable device to limit its output sound level to a maximum of 100 decibels, 94 decibels etc. Systems that automatically protect mobile equipment users from harmful sound levels are desirable.